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HKIMO 2026 THPT (Grades 10–12 shared) National Preliminary Set 03 Question 22

HKIMO · HKIMO 2026 THPT (Grades 10–12 shared) National Preliminary Set 03

Question 22

A box contains 3 black, 4 blue and 5 red balls. Four balls are drawn at random. Find the probability of drawing at least two blue balls.
  1. $\frac1{11}$
  2. $\frac{85}{99}$
  3. $\frac{67}{165}$
  4. $\frac{10}{11}$